21807223 has 2 divisors, whose sum is σ = 21807224. Its totient is φ = 21807222.

The previous prime is 21807211. The next prime is 21807241. The reversal of 21807223 is 32270812.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21807223 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21807283) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10903611 + 10903612.

It is an arithmetic number, because the mean of its divisors is an integer number (10903612).

Almost surely, 2^21807223 is an apocalyptic number.

21807223 is a deficient number, since it is larger than the sum of its proper divisors (1).

21807223 is an equidigital number, since it uses as much as digits as its factorization.

21807223 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 21807223 is about 4669.8204462270. The cubic root of 21807223 is about 279.3830933366.

The spelling of 21807223 in words is "twenty-one million, eight hundred seven thousand, two hundred twenty-three".